Electrorheology of suspensions of poly(ethylene glycol)/poly(vinyl alcohol) blend particles

We studied the electrorheology (ER) of poly(ethylene glycol) (PEG)/poly(vinyl alcohol) (PVA) blend suspensions. For neat PEG suspension, chain networks between two parallel plates could be observed with the naked eye and yield stress was detected. But a lot of particles were aggregated on the lower negative electrode. On the other hand, all PVA particles assemble under the upper positive electrode. Even if neat PVA suspension does not show the ER, PEG/PVA blend (PVA 10–20 wt%) suspension shows higher yield stress than neat PEG suspension. From the result of PEG/NaCl suspension, this interesting phenomenon is not caused by the ionic impurity. For PEG particles aggregating on the negative electrode, it is easy to move for the positive electrode by blending PVA. However, PVA itself does not show the ER and excess PVA decreases yield stress.